Characterization of Secondary Structure Transformation of Stretched and Slenderized Wool Fibers with FTIR Spectra

Abstract

Characterizations of wool fibers were performed with FTIR testing technology for two categories of stretched wool fibers, i.e., the OPTIM^TM-Fine wool, and the stretched wool processed on TJGD-ERDOS 02 stretching equipment, developed at College of Textile Engineering, Tianjin Polytechnic University, Tianjin, China. It was observed that the two types of stretched wool fibers could be characterized by the IR transmittance peaks at 1620 ∼ 1630 cm^-1 and 1510 ∼ 1520 cm^-1. It was evidenced that upon stretching the secondary structure of the wool fibers transformed from alpha helix, the typical secondary structure of raw wool, to beta pleated sheet, the typical secondary structure of native silk, which was supported by the change in cross-sectional morphology and stress-strain curve.